As the Fairmount Commuter Rail line train peeled away from Readville one morning, a conductor began collecting fares on the only car open to passengers. Scanning rows of empty seats, he realized the task would be easy.

“Only four people on the train,’’ he said, as he walked away.

Since 2005, the MBTA has spent more than $200 million on massive improvements to the Fairmount line to return rapid transit to sections of the city’s disadvantaged communities that had been cut off. But as the T prepares to open two stations on the track next month, ridership is dismally low.

Trains don’t run frequently, fares vary, and bus dependent commuters who made do without rapid transit service are all not ready to come on board.